• Title/Summary/Keyword: Pyridines

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Synthesis of Several New Isoxazole, Imidazo[1, 2-a]pyridine, Imidazo[1, 2-a]pyrimidine, Benzoxadiazine and Benzothiazine Derivatives from Hydroximoyl Halides

  • Abdelhamid, Abdou O.;Abdou, Sadek E.;Mahgoub, Sayed A.
    • Archives of Pharmacal Research
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    • v.15 no.4
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    • pp.317-321
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    • 1992
  • Furoyldroximoyl chloride 3d reacted with 2-aminopyridine, 2-aminopyrimidine. O-aminophenol, O-phenylenediamine and aminothiophenol to afford imidazo [1, 2-a]pyridine 6. imidazo[1, 2-a]pyrimidine 8, benzoxadiazine 10, nitrosobenzopyrizine 13a and nitrosobenzothiazine 13b, respectively. Isoxazoline 18 and pyrrolidino[3, 4-d]isoxazolin-4, 6-dione derivatives 19a and 19b obtained by the reaction of 3 with acrylonitrile and N-arylmaleimide. Hydroximoyl chloride 3 reacted with thiophenol and sodium benzene-sulfinate to yield furylglyoxaloxime 16a and 16b, respectively. Hydroximoyl chloride 3 reacted also with some active methylene compound to give isoxazole derivatives 20-23, respectively.

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Effect of Heat Treatment on CO2 Adsorption of Ammonized Graphite Nanofibers

  • Meng, Long-Yue;Cho, Ki-Sook;Park, Soo-Jin
    • Carbon letters
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    • v.11 no.1
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    • pp.34-37
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    • 2010
  • In this work, graphite nanofibers (GNFs) were prepared by ammonia and heat treatment at temperatures up to $1000^{\circ}C$ to improve its $CO_2$ adsorption capacity. The effects of the heat treatment on the textural properties and surface chemistry of the GNFs were investigated by $N_2$ adsorption isotherms, XRD, and elemental analysis. We found that the chemical properties of GNFs were significantly changed after the ammonia treatment. Mainly amine groups were formed on the GNF surfaces such as lactam groups, pyrrole and pyridines. The GNFs treated at $500^{\circ}C$ showed highest $CO_2$ adsorption capacity of 26.9 mg/g at 273 K in this system.

Synthesis of Certain Mercapto and Aminopyrimidine Derivatives as Potential Antimicrobial Agents

  • El-Kerdawy, M.M.;Eisa, H.M.;El-Emam, A.A.;Massoud, M.A.;Nasr, M.N.
    • Archives of Pharmacal Research
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    • v.13 no.2
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    • pp.142-146
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    • 1990
  • Reaction of ethyl 4-chloro-2-phenylpyrimidine-4-carboxylate (4) with 5-chloro-2-methylthiophenol or 3-aryl-4-phenyl-1, 2, 4-triazole-5 thiol yielded the corresponding thioethers (5) and (8a, b), respectively. Careful alkaline hydrolysis of (5) yielded the corresponding carboxylic acid (6). Reaction of (4) with p-aminoacetophenone yielded compound (10) which was reacted with certain aromatic aldehyde to afford the$\alpha,\beta$-unsaturated ketones (11a-d). Condensation of (11a-d) with malononitrile or phenylhydrazine yielded the 2-amino-3-cyanopyridines (12a-f) or the 2-pyrazolines (13a, b) respectively. Seven representative compounds were tested for their in vitro antimicrobial activity against some pathogenic micro-organisms, some of them were proved to be active.

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Heterocyclic Synthesis with Nitriles: New Routes for Synthesis of Pyridazines, Pyridines and their Fused Derivtives

  • Negm, Abdalla-M.;Abdelrazek, Fathy-M.;Elnagdi, Mohamed-H.;Shaaban, Lina-H.
    • Archives of Pharmacal Research
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    • v.17 no.6
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    • pp.411-414
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    • 1994
  • Phenylazocyanothioacetamide 1 reacts with malononitrile to afford the pyridinethione 4 which reacts with phenacylbromide to yield the pyridine-S-phenacyl derivative 6, 1 reacts with ethyl cyanoacetate to yield the pyridazine derivative, 8, and with phenacyl bromide to afford the N-phenacyl derivative 11, instead of the thiazole 10. Compound 11 afforded the pyrazolopyridine 13 on reaction with malononitrile while 10 was obtained on coupling of the thiazole 14 with diazotised aniline. Compound 10 reacts with malononitrile to afford the thizaolyl pyridazine 15. Compound 1 reacts with malononitrile dimer to afford the pyriodopyridazine derivative 17a. 1 reacts also with active methylene heterocycies to afford the pyrazolo and thiazolo-fused phridazines 20 and 23 respectively.

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Synthesis and Reactions of New Thienopyridines, Pyridothieniopyrimidines and Pyridothienotriazines

  • Bakhite, E.A.;Abdel Rahman, A.E.;Mohamed, O.S.;Thabet, E.A.
    • Bulletin of the Korean Chemical Society
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    • v.23 no.12
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    • pp.1709-1714
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    • 2002
  • 4-Aryl-3-cyano-6-(2'-thienyl)-pyridine-2(1H)-thiones(1a-c) were reacted with phenacyl bromide, chloro-N-arylacetanmides or 2-chloroacetylaminopyridine to furnish 2-functionalized 3-amino-4-aryl-6-(2'-thienyl)-thieno[2,3-b]pyridines 4a-c and 5a-c or 5d respecitively. The compounds 5a-d underwent different sequence of reactions to produce a variety of thienylpyridothienopyrimidines and, thienylpyridothienotriazines. Some of the prepared compounds were tested in vitro for their antimicrobial activities.

Kinetics and Mechanism of the Pyridinolysis of Aryl Cyclopropanecarboxylates in Acetonitrile

  • Koh, Han-Joong;Kang, Suk-Jin;Kim, Cheol-Ju;Lee, Hai-Whang;Lee, Ik-Choon
    • Bulletin of the Korean Chemical Society
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    • v.24 no.7
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    • pp.925-930
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    • 2003
  • Kinetic studies of the reaction of Z-aryl cyclopropanecarboxylates with X-pyridines in acetonitrile at 55.0 ℃ have been carried out. The reaction proceeds by a stepwise mechanism in which the rate-determining step is the breakdown of the zwitterionic tetrahedral intermediate, $T^{\pm}$. These mechanistic conclusions are drawn base on (i) the large magnitude of ρx and ρz, (ii) the positive sign of ρxz and the larger magnitude of ρxz than normal $S_N2$ processes, (iii) a small positive enthalpy of activation, Δ$H^≠$, and a large negative, Δ$S^≠$, and lastly (iv) adherence to the reactivity-selectivity principle (RSP) in all cases.

Pyridinolysis of O-Aryl Phenylphosphonochloridothioates in Acetonitrile

  • Lumbiny, Bilkis Jahan;Adhikary, Keshab Kumar;Lee, Bon-Su;Lee, Hai-Whang
    • Bulletin of the Korean Chemical Society
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    • v.29 no.9
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    • pp.1769-1773
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    • 2008
  • fThe kinetics and mechanism of the reactions of Y-O-aryl phenylphosphonochloridothioates with X-pyridines are investigated in acetonitrile at 35.0 ${^{\circ}C}$. The negative value of the cross-interaction constant, $\rho$XY = −0.46, indicates that the reaction proceeds by concerted $S_N2$ mechanism. The observed $k_H/k_D$ values involving d-5 pyridine ($C_5D_5N$) nucleophiles are greater than unity (1.05-1.11). The net primary deuterium kinetic isotope effects, $(k_H/k_D)_{net}$ = 1.28-1.35, excluding the increased $pK_a$ effect of d-5 pyridine are obtained. The transition state with a hydrogen bond between the leaving group Cl and the hydrogen (deuterium) atom in the C-H(D) is suggested for the studied reaction system.

Reaction Intermediate of Organic Sulfur Compound Ⅰ. Elimination Mechanism of Sulfonyl Chloride

  • Tae-Seop Uhn;Jong-Pal Lee;Hyun-Seok Park;Hyung-Tae Kim;Zoon-Ha Ryu
    • Bulletin of the Korean Chemical Society
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    • v.11 no.1
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    • pp.60-64
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    • 1990
  • The reactions of alkanesulfonyl chlorides with pyridines in the presence of various solvents have been studied by means of kinetic method. Alkanesulfonyl chlorides bearing ${\alpha}$-hydrogen with the normal attack of pyridine is found to be at the ${\alpha}$-hydrogen with elimination to form the sulfene intermediate evidently. From the mass spectra by the reaction of ethanesulfonyl chloride with 3-picoline in the presence of methanol-$d_1$, it has shown that the reaction has a witness favorable to the slulfene intermediate.

Photochemistry and Thermochemistry of Picolyl Chlorides

  • Shim, Sang-Chul;Kim, Sung-Sik
    • Bulletin of the Korean Chemical Society
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    • v.3 no.3
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    • pp.110-115
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    • 1982
  • Thermochemistry and photochemistry of picolyl chlorides were studied. The thermal reaction of 2-picolyl chloride in benzene afforded intermolecular condensation product. In the case of 3-picolyl chloride, this type of the reaction did not occur, but polymers were obtained. A cyclic hexamer, suggested by a molecular model, was not formed because of the steric strain and low reactivity. The thermal reaction of 4-picolyl chloride gave a cyclic hexamer as well as a polymer. The cyclic hexamer, identified by NMR spectrum, showed ${\lambda}_{max}$ at 460 nm. The cyclic hexamer was cloven to the linear structure. Photolysis of 2-picolyl chloride at 253.7 nm gave a para-isomer followed by polymerization. When a methyl hydrogen of 2-methylpyridine is substituted by $CH_3O$, iso-PrO, and EtO group, the photoisomerization to the corresponding anilines or para-substituted pyridines did not occur within the range of the time used for 2-picolyl chloride. Thermolysis of picolyl chlorides in an acidic methanol solution did not afford any product.

Reaction Intermediate of Organic Sulfur Compund Ⅱ. Nucleophilic Substitution Reaction of Disulfonyl Chloride Compounds

  • Dae-Dong Sung;Dae-Il Jung;Kyu-Chul Kim;Yang-Hee Kim;Soo-Dong Yoh
    • Bulletin of the Korean Chemical Society
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    • v.11 no.1
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    • pp.65-69
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    • 1990
  • The nucleophilic substitution reactions of naphthalene-1,5-disulfonyl chloride and 4-fluorosulfonylbenzenesulfonyl chloride with p-substituted anilines and methyl substituted pyridines in methanol-acetonitrile mixtures and hydrolyses of those disulfonyl halides have been studied by means of conductometric and polarographic methods. A large difference in the selective parameter, ${\rho}_N$ between mono-sulfonyl chloride and disulfonyl halide can be taken as an evidence that the second $SO_2Cl$ grolup of naphthalene-1,5-disulfonyl chloride also takes part in the reaction in contrast to sulfonyl fluoride in 4-fluorosulfonylbenzenesulfonyl chloride, which only acts as a substituent in the nucleophilic substitution reaction.